Item Template in the ItemPresenter - silverlight

Question

In this template ItemPresenter just defines host panel for the Items.
Is it possible to define ItemTemplate?
<ControlTemplate x:Key="ItemsControlTemplate" TargetType="ItemsControl">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<ScrollViewer>
<ItemsPresenter Width="{TemplateBinding Width}" Height="{TemplateBinding Height}"/>
</ScrollViewer>
</Grid>
</ControlTemplate>
To go further, I've created a class:
public class ItemsControlExtended : ItemsControl
{
public ItemsControlExtended()
{
DefaultStyleKey = typeof(ItemsControlExtended);
}
}
And I would like to create a dependency property "ItemsMargin".
After I've done that I'm supposed to bind an Item "Margin" property to "ItemsMargin".
How it would be possible to implement?
GetContainerForItemOverride ?
PrepareContainerForItemOverride ?
OnApplyTemplate ?

Answer 1

You can't define the ItemTemplate from with the ControlTemplate for the control as a whole.
Instead you would create a style that includes your control template and the the other templates as required:-
<Style x:Key="ItemsControlStyle" TargetType="ItemsControl>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ItemsControl">
<!-- your template as above -->
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate>
<!-- An alternative to StackPanel if so desired -->
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
<Setter Property="ItemTemplate">
<Setter.Value>
<DatalTemplate>
<!-- The item template you wanted -->
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
Now you can style the ItemsControl:-
<ItemsControl Style="{StaticResource ItemsControlStyle}">